1. Field of the Invention
The present invention relates to cursor control technology and more particularly, to a control device, which employs a non-contact sensing technique to detect a linear displacement of a movable member by sensing the change of the strength of the magnetic field emitted by a magnet at one of the two ends of the movable member, avoiding any mechanical fatigue or contact failure.
2. Description of the Related Art
Following fast development of the modern technology and electronic industry, many different kinds of consumer electronics, such as computer, mobile telephone, digital camera, personal digital assistant, multimedia player and etc., have entered into our daily life. Nowadays, computer has become an important tool and is intensively used by people daily. Further, following the development and popularization of home and office networks, people can use the internet to search information, listen to music, watch movies and TV news, play on-line games, send and receive e-mails, make on-line shopping, on-line subscription and on-line payment.
Further, a computer has multiple functions, bringing convenience to the user. Further, a computer may be equipped with a keyboard and/or mouse for controlling a cursor on a display screen for menu item selection, cursor dragging or other operations. When operating a computer mouse, a user may rest the wrist of the hand on the desk or a mouse pad and then move the computer mouse or click the button of the computer mouse with the fingers. However, when going to move the computer mouse over a big area, the user must lift the wrist from the desk or mouse pad. Excessive or improper use of a computer may cause pain in the wrist (the so-called carpal tunnel syndrome). In order to eliminate this problem, wrist rests are created. A wrist rest is a device used to support the wrist while typing or when using a computer mouse. However, leaning the wrists on a wrist rest for long periods can put a lot of pressure on the undersides of the wrists. This may cause carpal tunnel syndrome to develop. Actually, a wrist rest does help align the user's hands and wrists while mousing. Further, an improperly used wrist rest may actually cause more repetitive stress injuries for those who mouse for extended periods of time.
To avoid wrist injury, a wrist pad may be used. However, when operating a mouse, the user may lift the hand from the wrist pad to move the mouse, lowering the practicability of the wrist pad. Therefore, computer manufacturers are trying hard to create orthopedically engineered computers and computer peripheral devices. FIG. 11 illustrates a cursor control device for computer according to the prior art. According to this design, a rolling bar is provided for rotating by the user to control the cursor. However, the rolling bar is not movable axially to trigger a control switch. An extra swivel member may be used and drivable by the rolling bar to trigger a control switch. However, in actual application, the swivel member may be not accurately driven to trigger the control switch due to user operating habit or insufficient applied force. In this case, the user may have to operate the rolling bar repeatedly. To ensure accurate trigger, the user may have to apply much pressure to the rolling bar in driving the swivel member to trigger the control switch. Frequently operating the control device in this manner may damage the swivel member easily. When the swivel member fails, a repair work will be necessary.
Therefore, it is desirable to provide an orthopedically engineered control device that eliminates the aforesaid problems.